Conventionally, there has been known a disc device of this type, which includes an information processing section that reads out information recorded on an optical disc and/or records information on an optical disc, a transfer mechanism that transfers the information processing section to a predetermined position and a conveying mechanism that carries an optical disc into an internal predetermined position and takes out the optical disc therefrom.
The transfer mechanism or the conveying mechanism is provided with an interlocking mechanism such as an arm or a cam member. The interlocking mechanism is coupled with a driving source such as a motor. The cam member is provided with one of various switch mechanisms for controlling the driving source.
Some switch mechanisms include a switch 100, a switch body 102 of which is provided with a contact point 101 adapted so as to come out and to be pressed in, and a cam member 200 arranged so as to reciprocate in directions orthogonal to the in-and-out direction of the contact point 101 of the switch 100 as shown in FIGS. 1A to 1D and FIGS. 2A to 2D.
The cam member 200 has a cam surface 201 and non-cam surfaces 202 formed at ends of the cam surface 201. When the contact point 101 is in contact with the cam surface 201, the switch is On. When the contact point is at a position corresponding to the non-cam surfaces 202, the switch is Off. Reciprocation of the cam member 200 turns the switch On and Off. In the disc device, since a complicated control is required, the cam member 200 reciprocates in a complicated manner.
The switch 100 is adapted to be Off when the contact point 101 of the switch 100 is out of contact with the cam surface 201 of the cam member 200 and is at a position corresponding to the non-cam surface 202 as shown in FIG. 1A. From this state, when the cam member 200 advances in a direction indicated with an arrow P, the contact point 101 comes into contact with the cam surface 201 and is pressed into the switch body 102 as shown in FIG. 1B, thereby turning the switch 100 On. At this time, since a small friction is generated between the contact point 101 and the cam member 200, an end of the contact point 101 is pulled to be inclined in the movement direction of the cam member 200.
While the cam member 200 further advances, the switch 100 is kept On as shown in FIG. 1C. Then, the contact point 101 of the switch 100 comes out of contact with the cam surface 201 of the cam member 200 as shown in FIG. 1D and comes to a position corresponding to the non-cam surface 202, thereby turning the switch 100 Off.
When the cam member 200 retracts in a direction indicated with an arrow Q opposite to the direction of the arrow P as shown in FIG. 2A, the contact point 101 comes into contact with the cam surface 201 again and is pressed into the switch body 102, thereby turning the switch 100 On. At this time, the end of the contact point 101 is inclined in an opposite direction of FIG. 1B. The cam member 200 retracts to a predetermined position and stops there as shown in FIG. 2B. After the cam member 200 advances again, the cam member 200 retracts as shown in FIG. 2C and then advances, the contact point 101 of the switch 100 comes out of contact with the cam surface 201 of the cam member 200 again and comes to a position corresponding to the non-cam surface 202, thereby turning the switch 100 Off. Herein, the direction of the inclination of the end of the contact point 101 is the same as the inclination shown in FIG. 2A but the opposite of the inclination shown in FIG. 1B.
Comparing to the switch mechanism shown in FIG. 1D with the switch mechanism shown in FIG. 2D, the both are the same in that the contact point 101 is at a position apart from the cam surface 201 as a result of an advancement of the cam member 200, but are different in directions of the inclination of the contact point 101 immediately before coming to the position. Therefore, in the switch mechanism, the sensitivity of the switch varies due to a hysteresis generated on the switch 100.
In order to eliminate a disadvantage due to the hysteresis, software has been proposed which contains information on differences in operation of the contact point 101 depending on the directions of the movement of the contact point 101 in order to adjust the differences by changing an operation time.